// Copyright (c) 2008 Davy Brion (ralinx@davybrion.com)
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// 
//     * Redistributions of source code must retain the above copyright notice,
//       this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright notice,
//       this list of conditions and the following disclaimer in the documentation
//       and/or other materials provided with the distribution.
//     * Neither the name of Davy Brion nor the names of the
//       contributors may be used to endorse or promote products derived from this
//       software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

using System;
using System.Data;
using System.Diagnostics;
using Agatha.Common;


namespace EntityFramework.ServiceLayer
{
    public class UnitOfWork : Disposable, IUnitOfWork
    {
        private IObjectContext objectContext;
        private readonly bool isRootUnitOfWork;
        private IActiveObjectContextManager activeObjectContextManager;

        public UnitOfWork(IObjectContextProvider objectContextProvider, IActiveObjectContextManager activeObjectContextManager)
        {
            Debug.WriteLine("Debug message: Creating UnitOfWork");

            this.activeObjectContextManager = activeObjectContextManager;

            if (activeObjectContextManager.HasActiveObjectContext)
            {
                isRootUnitOfWork = false;
                objectContext = activeObjectContextManager.GetActiveObjectContext();
            }
            else
            {
                isRootUnitOfWork = true;
                objectContext = objectContextProvider.Create();
                activeObjectContextManager.SetActiveObjectContext(objectContext);
            }
        }

        public bool ReadOnly { get; set; }

        public void Flush() {}

        public ITransaction CreateTransaction()
        {
            return CreateTransaction(IsolationLevel.ReadCommitted);
        }

        public ITransaction CreateTransaction(IsolationLevel isolationLevel)
        {
           return new Transaction(objectContext.BeginTransaction(isolationLevel));
        }

        protected override void DisposeManagedResources()
        {
            Debug.WriteLine("Debug message: Disposing UnitOfWork");

            if (isRootUnitOfWork)
            {
                if (objectContext != null)
                {
                    objectContext.Dispose();
                }

                activeObjectContextManager.ClearActiveObjectContext();
            }
        }
    }
}